The present invention relates to an in-line roller skate.
Conventional skates are substantially constituted by a rigid shoe associated with a frame for supporting either wheels or an ice-skating blade.
The main drawback of conventional skates is the fact that the rigidity of the shoe or of the frame for supporting the wheels or the ice-skating blade prevent the normal articulation of the foot during skating.
U.S. Pat. No. 1,603,588 discloses a soft shoe having a sole associated with either a blade, constituted by two separate components which are mutually articulated approximately in the region below the plantar arch, or with a wheel supporting frame, which is again composed of two parts which are mutually hinged in the region below the plantar arch.
Although the above skate allows the articulation of the shoe and therefore of the foot during skating, a considerable drawback is constituted by the fact that the hinge for the mutual articulation of the parts of the blade or of the wheel support is far backward and entails a difference in the position of the rotation axis of the foot with respect to the shoe and the frame or blade.
In this manner, the natural rotation of the metatarsal region is compromised because the sole of the shoe is rigid at this region of the foot, while the sole of the shoe moves with respect to the foot, thus reducing its sensitivity with respect to said shoe and accordingly compromising optimum control and steering of the skate.
EP-0 686 412 discloses a roller skate with improved fit which is constituted by a first front body, for supporting and securing the front part of the foot, and by a second rear body, for supporting and securing at least the heel; said bodies are transversely and rotatably associated with each other, and each body is provided with a frame for supporting one or more wheels.
The two elements are rotatably connected to each other by means of studs or pivots and the movement is guided by a tab which protrudes from the front element and is arranged on the front part of the sole and of the shell.
In the above skate, the studs or pivots that are fixed to the side walls of the shell are subjected to a large number of movements and stresses caused by sports practice. In the course of time, these movements can compromise the efficiency and in particular the alignment of the first front body and of the second rear body.
It is also noted that the limited length of the elements for mutually connecting the first body and the second body tends to compromise the torsional properties of the entire skate and does not ensure the performance required for correct and comfortable use.
CA-2,155,444 discloses a skate which comprises a shoe whose sole has one or two transverse hinges formed approximately at the region where the foot flexes. In order to allow articulation, below the region of the tip of the shoe there is an additional hinge for an ice-skating blade which is associated, in a rear region, with the sole of the shoe so as to allow the articulation of said shoe.
A similar configuration is provided if the shoe is associated with a frame for supporting in-line wheels.
The above skate follows the natural movement of the foot, but at the same time it does not ensure the adequate technical characteristics required for sports practice, because, for example, the seat for the frame or blade provided in the rear region of the shoe is formed with plays which allow it to perform a combined rotary and translatory motion. This in no way ensures adequate lateral support and torsional strength, particularly during side-slip braking, which is notoriously the most trying step for the rear region of the skate.
EP-0 774 282 discloses a skate with in-line wheels which comprises a shoe associated a wheel supporting frame which has, approximately in a median region, a cutout which divides the frame into two components and forms a deformable region which allows the articulation of the two components of the frame. An elastic element is interposed between said components and is adapted to improve their return to the horizontal position.
In the above skate, it is noted that the deformation region, and therefore the corresponding flexing region of the shoe, do not meet the anatomical requirements of the foot because it is observed that the position of the rotation axis is distinctly too far back with respect to the natural axis of rotation of the metatarsus.
WO-97/18019 discloses a skate which is again composed of a shoe associated with a wheel supporting frame which is composed of two half-frames frames which are mutually rotatably connected by means of a common mechanical hinge which is located approximately in the vicinity of the axis of the second wheel starting from the front end of the shoe.
An elastic element is inserted approximately in the region located directly above the hinge, and its ends rest at the two half-frames, so as to facilitate the return of said two half-frames to the initial position.
One drawback that can be noted is the position of the elastic element which, by being very close to the hinge, considerably reduces the sensitivity of said hinge to small movements or depressions in the ground, thus making the skate very rigid and in practice limiting the flexing of the foot considerably.
An aim of the present invention is to solve the above-mentioned problems, eliminating the drawbacks of the cited prior art by providing a skate which allows the foot to perform, as much as possible, a natural movement while skating.
An object of the invention is to provide a skate which effectively follows the natural flexing of the foot during skating.
Another important object is to provide a skate which allows to accumulate, during the flexing of the foot, energy which then be returned during the final step of thrusting.
Another important object is to provide a skate which maintains its rigidity characteristics, which are necessary for its correct use.
Another object is to provide a skate which is structurally simple and can be manufactured with conventional machines and equipment.
In accordance with a preferred aspect of the invention, there is provided an in-line roller skate which comprises:
one single front wheel, one single intermediate wheel, and one or more rear wheels, in which the intermediate wheel is arranged between the front and rear wheels;
a first front frame which rotatably supports the front wheel about a front pivot axis lying in a front vertical plane, and the first front frame rotatably supports the intermediate wheel about an intermediate pivot axis lying in an intermediate vertical plane; and
a second rear frame which rotatably supports the one or more rear wheels about one or more rear pivot axes lying in respective one or more rear vertical planes;
the first and second frames being connected to a sole of the skate and said skate being pivotable about a skate pivot axis which is located at the sole of the skate in a region that lies approximately below the metatarsus of the foot, and the skate pivot axis lying in a vertical plane which extends between the front vertical plane and the intermediate vertical plane.